All About Amblyopia (lazy eye)

		Brief History of Treatment Methods for Helping Lazy Eye from 900 A.D. to Present by Susan R. Barry, Ph.D. Groundbreaking Research! Treatment After Age 7... New Scientific Research Contradicts Popular Beliefs and Medical Theories Regarding Age Limits for Successful Treatment of Lazy Eye by Susan R. Barry, Ph.D. and Rachel Cooper Age is Not a Limiting Factor in Fixing Lazy Eye or Amblyopia by Rachel Cooper Why Are Older Children, Teenagers and Adults with Lazy Eye Still Being Told That Nothing Can Be Done for Them? by neurobiologist Susan R. Barry, Ph.D. and Rachel Cooper Find Eye Doctors Find Eye Doctors Who Specialize in Treatment of Lazy Eye What is Vision Therapy for Lazy Eye - Non-surgical Treatment Successful Treatment of Lazy Eye in Children and Adults Surgery as Treatment for Lazy Eye The American Optometric Association (AOA) encourages parents to include a trip to the optometrist in the list of well-baby check-ups. Assessments at 6 to 12 months can determine healthy development of vision. Early detection of eye conditions is the best way to ensure your child has healthy vision. Find out more about free infant eye exams through the American Optometric Association InfantSee public health Program (as launched by former President Jimmy Carter on the Today Show). Go to InfantSee.org. The information on this advertising-free site is sponsored by Optometrists Network, Editor Rachel Cooper, with special thanks to the following non-profits: - American Optometric  Association (AOA) - College of Optometrists  in Vision Development (COVD) - Optometric Extension  Program (OEP)
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Amblyopia causes more visual loss
in the under 40 group than all the
injuries and diseases combined
in this age group.

SUMMARY:

• If not detected and treated early in life, amblyopia can cause loss of vision, including loss of depth perception and 3D vision (stereopsis).
• Improvements in vision can be achieved at any age, but early detection and treatment still offer easier treatment and the best outcomes.
• Neuroscience has proven that the human brain can change at any age (neuroplasticity). As a result, exciting scientific research is now taking place regarding the successful treatment of lazy eye in older children, teenagers, and adults.
• Comprehensive vision examinations are needed for infants and pre-school children. A vision screening by a pediatrician or the 20/20 eye chart screening is not adequate for the detection of amblyopia (and other visual conditions related to or mistakenly called lazy eye).

What is Amblyopia (Lazy Eye)?

Causes of Lazy Eye

Detection and Diagnosis of Lazy Eye

Treatment of Lazy Eye

Lazy Eye (Amblyopia) and Crossed Eyes (Strabismus) are not the same condition.

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What is Amblyopia (Lazy Eye)?
Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses or contact lenses and is not due to any eye disease. The brain, for some reason, does not fully acknowledge the images seen by the amblyopic eye. This almost always affects only one eye but may manifest with reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.

Causes of Lazy Eye

Amblyopia is a neurologically active process. According to researchers at New York University's Center for Neural Science, "Amblyopia results from developmental problems in the brain. When the parts of the brain concerned with visual processing do not function properly, problems ensue with such visual functions as the perception of movement, depth (depth perception), and fine detail (acuity, clear eyesight, sharp vision). Amblyopia is the most prevalent neurological defect of vision in children and adults, affecting 1-3 percent of the population."

Anything that interferes with clear unobstructed vision in either eye during the critical period of visual and brain development (birth to 6 years of age) could cause amblyopia. In addition, interference to or lack of simultaneous use of both eyes together (binocular vision) can cause what is called a "suppression" or "inhibition" response in the brain. In some cases, this suppression pattern can result in a decrease in the vision in the blurry eye that can not be corrected with glasses, lenses, or lasik surgery. Again, it is important to understand that the loss of vision is taking place in the brain. Notably, current research shows that the brain can change, develop, and recover at any age through active therapies.

Examples of visual conditions that can cause suppression and lazy eye in the brain:

1. one eye sees clearly and the other eye sees blurry (the brain will inhibit -- block, ignore, suppress -- the eye with the blur).
2. the two eyes do not aim at the same place, the brain will suppress one eye in order to avoid confusion and/or double vision (diplopia).
3. the two eyes have a significance difference in eyesight, visual perception or prescription (e.g., one is more nearsighted or farsighted than the other). In this case, the brain perceives two mismatching images and opts to throw one out (suppress) to avoid rivalry between the two eyes or double vision (diplopia).

The most common causes of amblyopia are constant strabismus (constant turn of one eye in any direction, but an inward turn or crossed eyes is much more common), anisometropia (differences in vision and/or prescription between the two eyes), and/or blockage of an eye due to cataract, trauma, lid droop (ptosis), blocked tear duct, etc. Other less common causes are reported to be congenital disorders and vitamin A deficiency.

Detection and Diagnosis of Lazy Eye
An eye exam by a pediatrician or the 20/20 eye chart screening is not adequate for the detection of amblyopia (and other visual conditions). The most important diagnostic tools are the special visual acuity tests other than the 20/20 letter charts currently used by schools, pediatricians and eye doctors. Examination with cycloplegic drops can be necessary to detect this condition in the young.

Since amblyopia usually occurs in one eye only, many parents and children are unaware of the condition. Many children go undiagnosed until they have their eyes examined at the eye doctor's office at a later age. Comprehensive vision evaluations are highly recommended for infants and pre-school children.

Treatment of Amblyopia (Lazy Eye)
Lazy eye is treatable. Neuroscience has proven that the human brain can change at any age (neuroplasticity). Treatment involves glasses, drops, eye patching, and/or vision therapy, including visual-motor and neurological therapies. Recent medical research has proven that lazy eye is successfully treated up to the age of 17 with therapies. See National Institutes of Health -- National Eye Institute; Older Children Can Benefit From Treatment; Lazy Eye.

Treatment of amblyopia after the age of 17 is not dependent upon age, but requires more effort including vision therapy.

To quote Dr. Leonard J. Press, FAAO, FCOVD: "It's been proven that a motivated adult with strabismus and/or amblyopia who works diligently at vision therapy can obtain meaningful improvement in visual function. As my patients are fond of saying: "I'm not looking for perfection; I'm looking for you to help me make it better". It's important that eye doctors don't make sweeping value judgments for patients. Rather than saying "nothing can be done", the proper advice would be: "You won't have as much improvement as you would have had at a younger age; but I'll refer you to a vision specialist who can help you if you're motivated."

Every amblyopic patient deserves an attempt at treatment.

Although improvements are possible at any age with proper treatment, early detection and treatment still offer the best outcome. Nevertheless, a desire for treatment at an early age should not motivate a rush to lazy eye surgery. When considering treatment options, it is important to understand that lazy eye results from problems in the brain (neurological deficit) and surgery commonly done for lazy eye is performed on the muscles on the outside of the eye(s) only. In many cases, lazy eye surgery will provide cosmetic benefits only and does not improve the patient's vision. Treatment options that are directed specifically toward vision improvement should be exhausted before eye muscle surgery is considered.

Lazy Eye (Amblyopia) and Crossed Eyes (Strabismus) are not the same condition.
Many people make the mistake of saying that a person who has a crossed or turned eye has a "lazy eye," but amblyopia and strabismus are not the same condition. Some of the confusion may be due to the fact that an eye turn can cause lazy eye. In other words, amblyopia can result from a constant unilateral strabismus (i.e., an eye that turns or deviates all of the time). Alternating or intermittent strabismus (an eye turn which occurs only some of the time) rarely causes amblyopia.

While a deviating eye (strabismus) can be easily spotted by the layman, amblyopia without strabismus or associated with a small deviation usually can be not noticed by either you or your pediatrician. Only an eye doctor comfortable in examining young children and infants can detect this type of amblyopia. This is why early infant and pre-school eye examinations are so necessary.

Due to misunderstanding or misuse of the terms for different visual conditions (i.e., deviating eyes vs. lazy eye), many people are inaccurately labelled as having a "lazy eye." If you think you or someone you know has lazy eye, learn more at Constant or Intermittent?, What is Convergence Insufficiency?, What is Double Vision?, What is Strabismus?, Exotropia, Esotropia, and Treatment Options.

Convergence Insufficiency is a fairly common visual condition which is also (1) confused with lazy eye; (2) not easily discernable to the observer and (3) not detected by the standard 20/20 eye test. Convergence Insufficiency is estimated to affect 5 out of 100 children and adults. See What is Convergence Insufficiency?

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References:

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